Escalators are provided with caliper disc brakes which are used to selectively prevent movement of the main drive sprocket shaft. These brakes will set whenever power to the escalator is shut off, either in an emergency situation, or when the escalator is shut down for servicing, or otherwise.
Escalators are made having different rises, or lengths, due to different building or architectural requirements. Longer escalators are of course heavier than the shorter ones, and therefore require a higher or larger braking force to hold the steps against movement. If a single common disc brake assembly is used for escalators of all rises or lengths, then the brake used must be capable of applying sufficient braking force to the drive shaft to hold in place the steps of the longest of the escalators using the brake. Thus the brake used must be capable of developing a high braking torque. When such a high torque brake is used on a short escalator, stoppage of the steps in emergency situations will occur in an undesirably abrupt manner. The only solution to this problem is to use different torque brakes for different length escalators, which creates manufacturing and inventory problems. At the present time, for preassembled escalators, the brakes are preadjusted and set in the factory. They cannot be tuned in the field. It would be desirable to have an escalator brake which has an adjustable torque so that the same brake assembly can be used for different length escalators, and so that the brake can be adjusted if necessary in the field.